Clutch mechanism for mechanical pencils



Oct. 3l, 1950 M. s. BAKER ET AL CLUTCH MECHANISM FOR MECHANICAL PENCILS2 Sheets-Sheet 1 Filed Aug. l0, 1948 5 Q 7 1 $42, ww/wgw mwy@ s. @2M/O,VA/2f) /fZ///fl i Q01 1 Rwma@ Mllll. W. 5. \.v\1 2 s Q w 3. TM ,A r/ 709 M 1 7 a 6%@ ozogmw @Dfw MNM M2M# d. w 1m 0t 31 1950 M. s. BAKER ETALCLUTCH MECHANISM FOR MECHANlCAL PENCIL-S Filed Aug. 1o, 1948 2Sheets-Sheet 2 Patented ct. 31:, t195i() s PATENT OFFICE 2,528,3.23V YCLUTCH MECHANISM FoR MECHANICAL v PENCILS Marlin S. Baker, Janes`lolpli, Milton, Wis.,

of Wisconsin ville, and Robert W. Rariassigiiors to The Parker PenCompany, Janesville, Wis., a corporation Application August 10, 1948,Serial No.- 43,468

(Cl. 1Z0-17) Claims.

This invention relates to mechanical pencils# .is fed progressively insteps by repeated actuation of the lead feed mechanism.

a lead actuating clutch therewith.

It is an object of the invention to provide a lead actuating clutch` fora mechanical pencil of the step-by-step type which may be made simplyand inexpensively from sheet material merely by punching and bending andwithoutk any machining operations.

Another object is to provide a mechanical pencil of the step-by-steptype having an actuating clutch carried on and frictionally engaging alead guideY tube 'for movement therewith and adapted, when restrainedagainst movement, to permit the latter to slide therethrough, in whichpencil the lead actuating clutch embodies improved means for maintainingthe frictional engagement with the lead guide tube.

Another object is to provide a lead guide tube for a mechanical pencilof the step-by-step type which may be detachably connected to the leadmagazine element for convenience in assembling Another object is toprovide a mechanical pencil of the step-by-step type wherein the leadguide tube is readily detachable from the lead magazine and may beremoved and replaced, if

desired, Without replacement of thelead magaz1ne.

'Other objects and advantages of the invention will appear from thefollowing description taken in connection with the appended drawings, inwhich:

Figure l is an enlarged fragmentary longitudinal sectional view throughthe forward portion of a mechanical pencil embodying my invention;

Fig. 2 is an enlarged fragmentary longitudinal sectional View throughthe rearward portion of the mechanical pencil;

Fig. 3 is a view similar to Fig. 1 only showing the lead-feedingmechanism in another operative position than shown in Fig. 1;

Fig. 4 is an enlarged transverse sectional view .taken along line 4-4 ofFig. 1;

Fig. 5 is an enlarged transverse sectional view taken along line 5--5 ofFig. 1;Y

Fig. 6 is an enlarged transverse sectional view Vtaken along line 6-6 ofFig. 1;

i Lliig. 8 is a perspective view of Fig. 7 is a perspective View of thecombined lead guide tube and point clutch forming a por- 'tion of thepencil of Fig. '1 Y lockA for connecting the lead guide tube to the leadmagaz1ne;

Fig. 9 is a perspective View of the lead actuating clutch;

Fig. 10 is a plan view of the blank from which the lead actuating clutchis formed;

Fig. ll is a fragmentary longitudinal sectional view illustrating amodified form of locking means for connecting the lead guide tube to themagazine;

Fig. 12 is a fragmentary longitudinal sectional View showing stillanother form of locking arrangement;

Fig. 13 is a transverse sectional View taken along line I3--I3 of Fig.12; and

Fig. 14 is a fragmentary exploded view of the vcooperating end portionsof the lead guide tube VA tapered tip l5, which preferably is formed ofmetal, is secured to the forward end of the barrel I0 as by a nippleportion I6 screwed into threads formed in the bore portion I3, the tipbeing firmly held in abutment against the end of the barrel as shown,with the nipple portion I6 extending rearwardly into the bore portionI2. The tip I5, as will be understood, forms with the barrel a housingor casing for the lead holding and feeding mechanism hereinafterdescribed and has a bore extending throughout its length, in alignmentwith the bore of the barrel, and comprising bore portions Il, I8, I9, 20and 2|, respectively, the purpose of which is described hereinafter.

The lead holding and feeding mechanism comprises a lead magazine 25which may be suitably formed by an elongate, generally tubular member 22open at its rear end and substantially closed at its forward end, as byan end member v23 which preferably serves also as a connector forconnecting to the magazine a lead guide tube 24 hereinafter more fullydescribed. The connector 23 may be secured to the tubular magazinemember 22 in any suitable manner and, in the present illustrativeembodiment, is secured by spinning a bead 26 into a circumferentialgroove formed in the connector 23. AY peripheral flange 21 is providedon the connector 23 against which the forward end of the tubular member22 abuts, which flange may also serve to guide the forward end of themagazine 25 in the bore portion l2.

The magazine 25 is adapted to contain a supply of leads of appropriatelengths, which leads are discharged successively from the magazinethrough a discharge opening 28 formed in the connector 23, the inner endwall 29 of the latter being tapered or convergent toward the opening 28in order to guide the forward end of a lead into the discharge opening.

The lead guide tube 24 is formed as an elongate tubular member and isadapted to receive leads successively from the discharge opening 28 andto guide them therefrom into a position in which a suitable portion ofthe forwardmost lead projects from the forward end of the pencil and isheld in a suitable position for writing. To this end, the lead guidetube is connected at its rearward end to the connector 23 in alignmentwith the discharge opening 28. The lead guide tube 24 extends throughthe bore of the tip l and projects slightly therefrom at its forwardend. The lead guide tube 24 carries at its forward end a point clutchwhich preferably is formed as an integral part of the tube. The forwardend portion 35i of the tube 24 is of reduced diameter and is providedwith a plurality of (preferably three) slits 3I extending inwardly fromthe forward end of the tube to provide clutch fingers 32, the forwardend portions of which are formed internally with inwardlyprojectingportions 33 which provide clutch jaws adapted to grip a leadtherebetween. The clutch fingers 32 are formed exteriorly with outwardlydivergent surfaces 3@ adapted to be contracted by the walls of the boreportion 2|, which are also outwardly divergent, when the point clutch isin its retracted position in the tip I5 as illustrated in Fig. l. 'Ihefingers 32 are resilient and are normally positioned so that the jaws 3Sdefine a bore of slightly less diameter than the diameter of the leadused in the pencil. Thus, these fingers provide a collet type Vclutchadapted to lightly grip a lead which is inserted therein. When the pointclutch is in retracted position, thejaw portions'of the fingers arewedged in the end of the tip and thus the lead guide tube is heldagainst further rearward movement. In addition, the clutch serves'toresist rearward movement of the lead therein when writing pressure -isapplied to the lead.

The lead guide tube 24, includingl the point clutch, is adapted to bereciprocated by corresponding movement of the magazine in the barrel andYwhen moved from its retracted position (Fig. l) to its projectedposition (Fig. 3) carries the lead forwardly to advance the leadrelatively to the pencil casing. For the purpose of preventing thereturn of the lead with the point clutch when the latter is retracted, alead actuating clutch 35 is provided which is adapted to grip the leadafter it has been advanced by the point clutch and to hold itsubstantially in its projected or advanced position, permitting thepoint clutch to be retracted without carrying the lead rearwardly. Thelead actuating clutch 35 (Fig. 9) includes an arcuate body portion whichat one end is formed with a substantially semi-circular cross-sectionalshape and is slitted, as at 36, inwardly from that end throughout asubstantial portion to dei-lne spaced friction arms 31 the remainingportion of the `body being unslitted. Extending radially inwardly fromthe side edges of the arcuate body portion at the slitted end thereofare retaining flanges 38 which are disposed in the diametrical chordalplane of the arc of the friction arms. Extending from the inner endedges of the retaining flanges 38 are lead gripping fingers 39 Awhichcarry at their free ends lead gripping jaws 40 which ngers and jaws liein the plane of the retaining flanges 38. The jaws 40 are formed attheir inner edges with lead gripping edge portions 4l and at their outeredges with inclined portions 42 adapted to cooperate with a clutchactuating sleeve hereinafter described.

The actuating clutch lends itself to formation from sheet metal bypunching and bending and without any machining operation. The clutchpreferably is formed by punching from a sheet of suitable metal, as forexample, beryllium, copper or brass, a blank such as the blank 43,having the general shape illustrated in Fig. l0. The fiat blank is thensuitably bent to form the arcuate body portion and thelappropriateportions of the blank bent inwardly therefrom so that the portions whichare to form the retaining flanges 38, the fingers '39 and the jawportions 4|] lie in a single plane as above described.

The actuating clutch 35 is assembled on the lead guide tube prior toattachment of the latter with the magazine, the lead guide tube beingprovided with diametrically disposed slots 44 which extend inwardly fromthe rearward end of the tube throughouta substantial portion of thelength thereof. The slots 44 are adapted to receive the retainingflanges 38, the fingers 39 and the jaws 4G. Thus, the clutch 35 isretained on the lead guide tube with the jaws 40 entering the slots 44and positioned to grip a lead disposed in the lead guide tube.

The fingers 39 of the actuating clutch are resilient and normallymaintain the jaws 40 out of engagement with a lead disposed in the leadguide tube. However, actuating means are provided for lcontracting thejaws against a lead in the tube slightly before the lead guide tubemoves into the retracted or rearward position. To this end, the nippleVportion I6 of the tip is formed with the bore portion I'! in which thejaws 40 reciprocate and which serves as a clutch actuating sleeve. Theinner end of the bore portion il is formed with a reduced diameter sothat when the jaws are in that portion of the sleeve, they arecontracted, but when the jaws are advanced out of rearward position,they are permitted to expand away from the lead. Preferably, there isprovided at the inner end of the nipple IG a clutch seat 49 which takesthe form of a'ring crimped in the inner end of the nipple and having aconverging surface portion 45 adapted to receive the edge portions 42 ofthe jaws and contract the jaws against the lead.

The lead guideV tube is detachably connected to the connector 23 invorder to permit the clutch 35 to be assembled with the tube. Preferablythe rearward end of the lead guide tube is telescoped in a socket 45formed in the forward end of the connector 23 which so'cketis so formedas to provide a rearwardly facing flange or shoulder 41 and the rearwardend'of the lead guide tube 24 is provided with a forwardly facingshoulder d8 adapted to engage behind the shoulder il to retain the leadguide tube in the socket 45. For the purpose of firmly clamping the endof the lead guide tube in the socket 4S, a lock 50 (see Fig. 8) isprovided, which is carried in the connector and is adapted to expand theend ofthe lead guide tube vin the socket 46 to maintain the shoulders 41and48 in engagement. The lock 58 has an arcuate body portion 5l adaptedto seat against the connector 23 with arcuate ngers"52 extendingtherefrom and adapted to flt ina peripheral groove 53 therein to retainthe lock on the connector and against a longitudinal displacement.Forwardly of the fingers 52 is a 'secondpair of fingers 54 which areturned inwardly at their end portions and extend through slots 55 of theconnector 23 and enter the slots 44 in the lead guide tube 24 to expandthe latter sufficiently to maintain the shoulder 48 in engagement behindthe shoulder 41 and thus lock the lead guide tube in the connector.

' The above described members are assembled by inserting the retainingflanges 38 of the clutch 35 in the ends of the slots 44 of the leadguide tube 24 and sliding the clutch 35 onto the lead guide tube 24. Thelock 58 is disposed on the connector 23, with the lingers 52 spreadapart vand the lock slid rearwardly on the connector to a positionwherein the fingers 54 are at the rear or bottom end of the slots 55.Thereafter, the rear end of the lead guide tube 24 is inserted in ythesocket 416 with the tube slots 44 aligned'with the slots 55 of theconnector 23. The lock 50 is then slid forwardly, with the fingers 54entering the slots 44 to prevent the rear end of the lead guide tube `24from being accidentally pulled out of the socket 46. The fingers k52 arethen bent inwardly to seat in the groove 53 and prevent longitudinaldisplacement of the lock 5U on the connector 23. l

The movable assembly, which includes the magazine 25, lead guide tube 24and actuating clutch 35, is normally urged rearwardly in the barrel l0by a retracting spring 1I which preferably takes the form of a coilspring seated at its forward end against a shoulder 56 formed at the'juncture of the bore portions Il and I2 and bearing at its rearward endagainst a thrust ring 51 rmly secured to the tubular member 22, in anysuitable manner. For example, the thrust ring 51 may be seated against ashoulder 58 and held by a tang 59 struck up from the tubular member 22.The tubular member 22 is slidable in and is retained in the barrel l0 bya barrel bushing 64 threaded in the rearward end of the barrel I0.

The tubular member 22 projects from the rearward end of the barrel IIJand preferably is formed with a socket portion 60 for receiving aneraser 6I which may be carried in an eraser cup 62 seated against aninternal bead 63. While the pencil may be actuated by depressing theprojecting end of the tubular member 22, or the eraser where one isprovided, preferably a cap 65 is provided which incloses the projectingend of the tubular member 22 and which cap is depressed to operate thepencil. The cap 65 may be formed in any suitable manner but preferablyincludes a liner 56 which telescopes over the end of the tubular member22 and has a flange 61 adapted to abut an external bead 68 on thetubular member 22 for limiting the telescoping movement of the cap on.

the tubular member 22 and for transmitting thrust to the latter. A capshell 69incloses the cap liner 66 and is secured thereto in a .knownmanner, as by a liner bushing 18 which receives a clip screw bushing 11into which is screwed a clip screw 18 adapted to secure a clip 19 on theend of the cap :65.

The pencil is charged with leads by removing cap v65 and the eraser 6|and by inserting one or moreleads inthe magazine 25 whereafter theeraser and cap are replaced.V The lead in the` magazine 25, or one ofthe leads where a plu-, rality are disposed in the magazine, enters thedischarge opening 28 when the pencil is placed in point down positionand passes into the rearward end of the lead guide tube. Upon depres-Vsion of the cap 65 and consequent forward move-I ment of the movableassembly (including they magazine 25 and the lead guide tube 24) theclutch 35 is advanced Yand the jaws 4U are perd mitted to open and allowthe lead to pass therethrough and the leading end of the lead contactsthe inner ends of the point clutch jaws 33. Y

When the pressure on the cap is released,'the retracting spring 1|returns the movable assembly to its rearward position. However, prior tothe completion of the return movement of the assembly, the clutch jaws40 enter the ring 45 and are contracted against the lead to securelyhold the lead against rearward movement. The remainder of the movableassembly continues to move rearwardly, the lead guide tube 24 beingmoved rearwardly with respect to the lead so-that the lead entersbetween the jaws 33 and thejaws are drawn back over the lead to exposethe forward end thereof.

Upon a second depression of the cap, the lead is carried forwardly withthe point clutch inasmuch as the jaws engage the lead with sufficientgrip to move it therewith. The leadactuating clutch 35 is also carriedforwardly into a position where the jaws are free of the ring and mayexpand by reason of their resiliency and release their grip upon thelead. Prior to the completion of the forward movement of the movableassembly the forward end of the lead actuating clutch 35 strikes theshoulder 80 defined between the bore portions i8 and I9 (see Fig. 3),thus halting further movement of the clutch 35. However, the lead guidetube 24 continues to move forwardly and carries the lead through theactuating clutch 35 a substantial distance. Forward movement of theassembly is halted when the forward end of the connector 23 strikes therear end of the nipple f I6, on the ring 49 where the latter projectsfrom the nipple. When the pressure on the cap is released the movableassembly, including the lead actuating clutch 35, moves rearwardly.After a short rearward movement of the clutch, the jaws 40 engage thering 49 and are contracted thereby to grip the lead and hold it againstrearward movement. The magazine and lead guide tube, however, continuerearwardly until the point clutch wedges in the bore portion 2! of thetip to halt further rearward movement of the assembly. During thislatter portion of the rearward movement of the lead guide tube it ismoved relatively to the lead with the result that a correspondinglygreater amount of lead projects from `the forward end of the pointclutch than before the just-described cycle of operation took place.

The means for detachably locking the leadl guide tube to the magazinemay take various; forms and two such additional forms are dis-` closedherein by way of illustration.

Referring now to Fig. l1, the locking means-- com'prises a lock 80formed with a funnel-shaped portion 8| which may serve as the end wallor floor of the magazine and a tubular portion 82 extending therefrom.The funnel-shaped portion is frictionally positioned in the magazine byengagement with the side wall member 83 with the tubular portion 82extending through an opening 84 in the connector 85. The lead guide tube86;

has a-slitted 'end formed witha circumferential groove 87 which engagesa lip -88 on the connector 85 and is locked in such position by thetubular portion 82. The lead Vguide tubefis assembled with the magazineby inserting itin the opening 84 land then inserting the tubular portion32 in the end of the lead guide tube. These members may be disassembledby inserting an expansible tool in the tubular 'portion and withdrawingthe tubular portion from the lead guide tube whereafter the latter maybe withdrawn from the connector.

Still another form o1" connector is shown in Figs. Y12 to 14 to whichreference now is made. In this form the connector is formed witha'reduced extension 90 having a socket 9| in which 'the slitted end ofthe lead guide tube 92 is inserted. The latter is formed with acircumferential groove 93 and a lock 94 of generally horseshoe form isprovided the legs of which extend through slots 95 in the connector 90and enter the groove 93. The ends of the lock 94 may be bent over asindicated atv 96 to prevent displacement of the lock. In order toprevent the endrof the lead guide tube from being accidentally pulledout of the socket, the connector is provided with ribs 9i' which enterthe slits in the tube and prevent contraction of the end of the tube.

From the foregoing it will be seen that the-.f

present invention provides a mechanical pencil ofthe step-by-step typewhich ispositive and certain in operation. At the same time, how-v ever,the construction is'relatively simple and lends itself to economicalmanufacture and.

assembly.

The lead actuating clutch is of simple construen tion and may be formedby merely punching al blank from sheet material and forming the blank.into final shape to constitute the clutch by simple: bending operations.The clutch may be readily `adjusted in the course of the assembly of thepencil to provide the desired frictionai engagement with the leadrguidetube to insure the best operation of the pencil. Moreover, should thelead. :actuating clutch become broken or require ad .justment orreplacement it may be removed read ily by merely disconnecting the leadguide tube from the magazine and removing the clutch from the lead guidetube. K

The lead guide tube, which includes the point'. 'clutch, may be formedvery easily and may be attached readily to the magazine in the assemblyoperation. Moreover, it may be readily removed and replaced withoutreplacement of the lead .magazine should replacement or" the guide'tubebecome necessary, as for example when it is fdamaged in use.

The present invention also provides a pencil which may be made small andcompact, if de -sired, without detriment to the necessary strength andeiiiciency of the lead propelling mechanism. Among the features whichcontribute to this re-v sult is the arrangement of the lead clutch withits jaws extending rearwardly and the position-- ing of the driving orretracting spring around themagazine.

We claim: Y d 1. A mechanical pencil of the step-by-step typeIvcomprising a casing, a lead magazine element slid-l I'able in saidcasing and having a lead discharge lopening in its forward end, springmeans urging said magazine element rearwardly in said casing, a leadguide tube in said casing having a lead clutch at its forward end andformed with'op-I 8 posed slots extending inwardly from its rearward end,a second lead clutch "slidably carried on said lead guide tube includinga` slotted arcuate lbody portion having opposed, fixed, retainingflanges at one end thereof, saidbody portion at least partiallyenclosing said tube'v with said iianges entering into said slots, andresilient lead engaging jaws projecting from the other end of said bodyportion and extending into said opposed slots, Aa clutch-actuatingelement carried by said casing in position' to engage and urge said jawsinwardly when said magazine element is urged rearwardly in said casing,and means for detachably connecting said lead guide tube to saidmagazine element for movement therewith and with said lead guide tube inposition to receive a lead from said lead discharge opening.

2. A mechanical pencil of the 'step-by-step l typey comprising acasing,a lead magazine-vele- `ment slidable in said casing and having alead discharge opening in its forward Vend, spring .means urging saidmagazine element rearwardly in said casing, a lead guide tube in saidcasing having a lead clutch at its 4forward end and iprmed with opposedslots extending inwardly :from its rearward end, a second lead clutchslidably carried on said lead guide -tube and having an arcuate bodyportion with opposed retaining :flanges extending inwardly from theedges thereci" A.at one end of said portion, said body portion at leastpartially enclosing said tube vwith said anges extending into saidopposed slots to retain said second clutch on said lead guide tube, saidsecond clutch having jaws in the plane of and extending rearwardly -fromsaid'fiianges and being disposed wholly rearwardly of said body portionand adapted to 4project through said opposed slots for engaging a-leadin-saidlead guide tube, a clutch-actuating element carried by saidcasing in position to vengage and urge said jaws inwardly when saidmagazine element is urged rearwardly in said casing, and means fordetach- ;a'bly connecting said lead guide tube to said lead magazineelement for movement therewith and with said lead Vguidetube inpositionto receive a lead from said lead discharge opening.

3. In a mechanical Ypencil of thenstep-bwstep type, in combination, alead magazine'element .having a socket formed'at its forward'end, and apoint clutch and vlead vguide comprising lan elongated tubular memberslotted inwardly from one end to deiine a'collet clutchrand slottedinwardly from the other end to define a pair of parallel ,y resilientmagazine-engaging fingers, -an internal shoulder formed in said socketand a cooperating external shoulder on the end oi each `of said ngersadapted to seat in said socket 'behind said internal shoulder to providea 'detachable snap-in connection between -said lead guide and'magazine,:and locking means formaintaining said fingers in yengagement withlsocket shoulder.

fi. A point clutch and lead guide for a mechan- :ical pencil of thestep-by-step type having a mov- .fable magazine element provided with'aninwardly rextending shoulder rat its forward end and comprising atubular member slotted'inwardly from 'its forward end to 'dene' a`collet clutch and formed with two diametrically aligned slots extendinginwardly from the rearward 'end and terminating short of saidfirst-'named slots to provide a `pair of rearwardly extending resilientmagazine-engaging liingers, and an arcuate shoulder .formed on each ofsaid lingers at the rearward Iend thereof vfor cooperationV with theshoulder on 'said magazine for detachably Aconnecting said` member tosaid magazine element.

5. An actuating lead clutch for mechanical pencils of the step-by-steptype having a diametrically slotted lead guide tube comprising anarcuate body portion slotted longitudinally throughout a portion of itslength to define spaced arcuate friction arms extending therefromdesigned to at least partially encompass the lead guide tube to maintainthe lead clutch slidably disposed on the tube, retaining flangesextending inwardly from the forward edges of said friction arms anddisposed substantially in a single plane and designed for entry intosaid slots, and spaced lead gripping jaws extending from corre- 10sponding rear ends' of said flanges and disposed substantially in theplane thereof likewise designed for-entry into said slots,

VMARLIN S. BAKER.

ROBERT W. RANDOLPH.

REFERENCES CITED The following references are of record in the file ofthis patent:

`UNITED STATES PATENTS Number Name Date 1,886,371 Bowman Nov. 8, 19322,179,835 Ward Nov. 14, 1939

